High-strength wire cable duct

ABSTRACT

A wire cable duct comprises a grid made up of wires of two different types, namely longitudinal wires which run longitudinally the entire length of the duct and U-shaped transverse wires disposed transversely to the longitudinal wires, from place to place along their length and appropriately attached thereto. The resulting trough-like combination forms three panels, namely a bottom panel and two side panels. The side panels comprise a longitudinal row of successive plane and substantially rectangular edge meshes which constitute upper parts of the side panels, each of which is defined between two facing flange portions of two consecutive transverse wires, and each of which includes at least one anti-flexing member to limit its flexing about an axis perpendicular to its plane.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to wire cable ducts.

[0003] 2. Description of the Prior Art

[0004] Prior art wire cable ducts take the form of a grid made up ofwires of two different types, namely longitudinal wires, usuallyreferred to as warp wires, which run longitudinally the entire length ofthe duct in a rectilinear or quasi-rectilinear manner and, disposedtransversely to the longitudinal wires, from place to place along theirlength and appropriately attached thereto, U-shaped transverse wires,usually referred to as weft wires, the combination forming three panelswhich in practice are plane or substantially plane, namely a bottompanel and two side panels, usually referred to as flanges.

[0005] They are routinely used as troughs to support, house and protectelectrical cables or the like.

[0006] Here and hereinafter the expression “electrical cables” refersnot only to cables adapted to convey and distribute electrical energybut also to cables and fibers adapted to transmit information inelectrical, optical or other form.

[0007] With regard to electrical cables, wire cable ducts have manyadvantages which are appreciated by electrical installers and inparticular the advantages of easy installation, and therefore economy,flexibility, because the electrical cables can exit through any mesh ofthe grid, transparency, and therefore of easy identification of theelectrical cables, ventilation, cleanliness, safety, both with regard tothe electrical cables themselves and users, and performance.

[0008] By virtue of their very design, the maximum span of the abovewire cable ducts is limited, as are the loads they are able to support:for this reason the inherent capacity of the trough shape is notcompletely utilized, unless the number of supports and jointing membersis increased, which is to the detriment of assembly time and thereforeto installation cost; also, the installation environment often rules outthe fitting of numerous supports.

[0009] The side panels comprise a longitudinal row of successivesubstantially rectangular and plane edge meshes which constitute theupper part of the side panels and each of which is defined between thefacing flange portions of two consecutive U-shaped transverse wires andbetween two longitudinal wires which cross over them. They sag to anon-negligible degree when heavily loaded.

[0010] An object of the present invention is to avoid the abovedrawbacks and to propose a wire cable duct with a longer span or higherloading capacity than prior art wire cable ducts; thus the presentinvention provides a high-strength cable duct.

[0011] The document FR-A-2 706 973 describes a cable duct of the abovekind which is made stronger by fixing reinforcing lateral spars to theside walls of a wire trough which overlie the side walls completely.

SUMMARY OF THE INVENTION

[0012] Numerous trials carried out by the inventors of the presentinvention have shown that, in order to increase the stiffness of ameshed cable duct, it is sufficient to limit flexing of only the edgemeshes, which is a simpler and less costly solution than that disclosedby the above prior art document.

[0013] Accordingly, the invention provides a wire cable duct comprisinga grid made up of wires of two different types, namely at least onelongitudinal wire which runs longitudinally the entire length of theduct and U-shaped transverse wires disposed transversely to thelongitudinal wires, from place to place along their length andappropriately attached thereto, the resulting trough-like combinationforming three panels, namely a bottom panel and two side panels, whichside panels comprise a longitudinal row of successive plane andsubstantially rectangular edge meshes which constitute upper parts ofthe side panels, each of which is defined between two facing flangeportions of two consecutive transverse wires, and each of which includesat least one anti-flexing member adapted to limit its flexing about anaxis perpendicular to its plane.

[0014] In a first embodiment each edge mesh consists of two longitudinalwires joined to facing flange portions of two transverse wires and toeach other by at least one crossmember. The crossmember is parallel tothe flange portions of the transverse wires. Alternatively, thecrossmember is inclined to the flange portions of the transverse wires.In another embodiment the crossmember has an open U-shape with a coreattached to one longitudinal wire and arms attached at their ends to theother longitudinal wire. The ends of the arms are preferably also joinedto the flange portions of the transverse wires at the intersectionthereof with the other longitudinal wire. The core of the open U-shapeis advantageously attached to an upper longitudinal edge wire. Thecrossmember is preferably a continuous wire which is adapted to limitflexing of consecutive meshes and is alternately connected to each ofthe longitudinal wires delimiting the meshes.

[0015] In another embodiment each edge mesh consists of a sectionattached to the flange portions of the transverse wires. The section isplane and attached to the outside and/or to the inside of the cableduct. Alternatively, the section has an L-shaped cross section defininga longitudinal rim. The section is attached to the outside or to theinside of the cable duct with its longitudinal rim overlying free endsof the flange portions of the transverse wires. The section is attachedto the outside of the cable duct with its longitudinal rim directedoutward. Thus in these embodiments the edge mesh does not include anylongitudinal wires.

[0016] In another embodiment the section has a U-shaped cross sectionwith wide flanges and straddles the flange portions of the transversewires.

[0017] In another embodiment the section has a U-shaped cross sectionwith narrow flanges and is attached to the outside of the cable ductwith its flanges directed outward. The narrow flanges are straight orhave a rolled edge.

[0018] The features and advantages of the invention will emerge furtherfrom the following description, which is given by way of example andwith reference to the accompanying diagrammatic drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a perspective view of a prior art wire cable duct.

[0020]FIG. 2 is a partial view of a wire cable duct according to theinvention.

[0021]FIGS. 3 and 4 are analogous to FIG. 2 and each corresponds to onevariant thereof.

[0022]FIGS. 5 and 6 show part of another embodiment of a wire cable ductaccording to the invention and FIG. 6 is a view in cross sectionrelative to FIG. 5.

[0023] FIGS. 7 to 13 are views analogous to FIG. 6 and each correspondsto one variant thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The wire cable duct 10 shown in FIG. 1 takes the form of a gridmade up of wires 11, 12 of two different types, namely rectilinear orsubstantially rectilinear longitudinal wires 11 which run its entirelength and U-shaped transverse wires 12 at regular intervals along andappropriately fixed to the longitudinal wires 11. This is known in theart. The resulting trough-like assembly comprises three panels, namely abottom panel 13 and two side panels 14.

[0025] In practice the wires 11, 12 are metal wires and more preciselysteel wires and are welded together at their crossing points 16.

[0026] By construction, the wires 11, 12 cross at different levels.

[0027] In practice the longitudinal wires 11 are at a lower level andare referred to as the lower wires and the transverse wires 12 are at anupper level and are referred to as the upper wires.

[0028] In other words, the longitudinal wires 11 extend along theoutside of the transverse wires 12, but a different construction couldof course be used, with the transverse wires 12 on the outside of thelongitudinal wires 11.

[0029] In the embodiment shown, all the wires 11, 12 are round wires. Inother words, they all have a circular cross section. Other shape crosssections are possible, however: square, rectangular, round with flats,polygonal or other shapes. The concept of diameter in the context ofthis application encompasses that of the width or thickness of the wire,depending on the shape of its cross section.

[0030] As shown here, for example, the diameter of the wire is the samefor all the wires, but this is not necessarily always the case.

[0031] In the embodiment shown, the bottom panel 13 includes threelongitudinal wires 11 and the longitudinal wires 11 and thecorresponding transverse wires 12 define one mesh in each pitch.

[0032] However, the number of longitudinal wires 11 constituting thebottom panel 13, and therefore the number of meshes that they define ineach pitch, can be different. In particular, in a variant that is notshown the bottom panel 13 includes only one longitudinal wire 11.

[0033] In the embodiment shown, each of the side panels 14 includes onlytwo longitudinal wires 11, namely an intermediate longitudinal wire 11substantially halfway up and an edge longitudinal wire 11. However, thenumber of longitudinal wires 11 can be different.

[0034] In particular, like the bottom panel 13, the side panels 14 candefine meshes which can be the same size as the meshes of the bottompanel 13 or a different size.

[0035] In the embodiment shown, the edge longitudinal wire 11 of theside panels 14 includes undulations 15 which are spaced by the pitch ofthe duct and abut against the transverse wires 12, but this is notnecessarily always the case.

[0036] Thus here the side panels 14 have along their upper edge alongitudinal row of successive meshes which are referred to as edgemeshes, which are substantially rectangular and plane, and each of whichis defined between the facing flange portions of two consecutiveU-shaped transverse wires 12 and between two longitudinal wires 11 thatcross over said flange portions.

[0037] In accordance with the invention, and as shown in FIG. 2, atleast one of the edge meshes is stiffened to limit its flexing about anaxis perpendicular to its plane, as a result of which the maximum spanof the wire cable duct can be increased.

[0038] A rigid edge mesh of the above kind therefore includes ananti-flexing member consisting in this embodiment of a wire crossmember17 linking the two longitudinal wires 11 defining the mesh, to which itis welded in this example.

[0039] In the FIG. 2 example there is a single crossmember 17 disposedparallel to the flange portions of the transverse wires 12, practicallyin the middle of the mesh. Several crossmembers like the crossmember 17can be provided, of course. FIG. 3 shows a rigid edge mesh having twosuch crossmembers, for example.

[0040] A variant that is not shown includes one or more wirecrossmembers inclined to the flange portions of the transverse wires 12.

[0041]FIG. 4 shows an anti-flexing member consisting of an open U-shapedwire crossmember 27 whose core is welded to the top longitudinal wire 11of the mesh in this example. The end of each arm of the U-shape isconnected to the other longitudinal wire 11, or preferably, as shownhere, to the intersection of the longitudinal wire 11 and the flangeportions of the transverse wires 12.

[0042] In a variant that is not shown a crossmember like the crossmember27 is part of a continuous wire joined alternately to the longitudinalwires 11 common to the successive meshes on respective opposite sides ofthe mesh shown in the figure. The continuous wire can of course beconformed to various shapes: trapezoidal, sinusoidal, broken line, etc.

[0043] In the variants shown in FIGS. 5 to 13 the anti-flexing member isin the form of a section, for example a metal section, which itselfconstitutes the rigid edge mesh, as it were; in the examples shown, thesections are sheet metal sections and are welded to the flange portionsof the transverse wires 12. The sheet metal can be perforated or solid.As can be seen in FIGS. 5 to 13, the mesh then has no longitudinalwires.

[0044] In FIGS. 5 and 6 the section 18 is plane and attached to theoutside of the cable duct. It can instead be inside the duct. In FIG.10, two such sections 18 are provided, one on the inside and the otheron the outside of the cable duct.

[0045] In FIG. 7 the section 28 has an L-shaped cross section andtherefore incorporates a narrow longitudinal rim. The width of the rimis advantageously equal to the diameter of the transverse wire 12 sothat the rim caps the free ends of the flange portions of the transversewires 12, whether the section 28 is on the outside of the cable duct, asshown in FIG. 7, or on the inside, as shown in FIG. 9.

[0046] The section 28 can of course be disposed so that its rim isdirected toward the outside of the cable duct, as shown in FIG. 8.

[0047] The section 38 shown in FIG. 11 has a U-shaped cross section withwide flanges and straddles the flange portions of the transverse wires12. The inside dimension of the base of the U-shape of the section 38 isequal to the diameter of the transverse wires 12.

[0048] The section 48 shown in FIG. 12 has a U-shaped section withnarrow flanges and is attached to the outside of the cable duct with thenarrow flanges directed toward the outside.

[0049] The section 58 shown in FIG. 13 is similar to the section 48shown in FIG. 12 except that the flanges of the section 58 have a rollededge extending toward the inside of the U-shape of the section.

[0050] Many trials have shown that the performance of a wire cable ductaccording to the invention, in terms of sag and loading, is improved byat least 15%, reflected in an increase in the maximum span between twoconsecutive supports.

There is claimed:
 1. A wire cable duct comprising a grid made up ofwires of two different types, namely at least one longitudinal wirewhich runs longitudinally the entire length of the duct and U-shapedtransverse wires disposed transversely to the longitudinal wires, fromplace to place along their length and appropriately attached thereto,the resulting trough-like combination forming three panels, namely abottom panel and two side panels, which side panels comprise alongitudinal row of successive plane and substantially rectangular edgemeshes which constitute upper parts of said side panels, each of whichis defined between two facing flange portions of two consecutivetransverse wires, and each of which includes at least one anti-flexingmember adapted to limit its flexing about an axis perpendicular to itsplane.
 2. The cable duct claimed in claim 1 wherein each edge meshconsists of two longitudinal wires joined to facing flange portions oftwo transverse wires and to each other by at least one crossmember. 3.The cable duct claimed in claim 2 wherein said crossmember is parallelto said flange portions of said transverse wires.
 4. The cable ductclaimed in claim 2 wherein said crossmember is inclined to said flangeportions of said transverse wires.
 5. The cable duct claimed in claim 2wherein said crossmember has an open U-shape with a core attached to onelongitudinal wire and arms attached at their ends to the otherlongitudinal wire.
 6. The cable duct claimed in claim 5 wherein the endsof said arms are also joined to said flange portions of said transversewires at the intersection thereof with said other longitudinal wire. 7.The cable duct claimed in claim 5 wherein said core of said open U-shapeis attached to an upper longitudinal edge wire.
 8. The cable ductclaimed in claim 5 wherein said crossmember is a continuous wire whichis adapted to limit flexing of consecutive meshes and is alternatelyconnected to each of said longitudinal wires delimiting said meshes. 9.The cable duct claimed in claim 1 wherein each edge mesh consists of asection attached to said flange portions of said transverse wires. 10.The cable duct claimed in claim 9 wherein said section is plane andattached to the outside and/or to the inside of said cable duct.
 11. Thecable duct claimed in claim 9 wherein said section has an L-shaped crosssection defining a longitudinal rim.
 12. The cable duct claimed in claim11 wherein said section is attached to the outside or to the inside ofsaid cable duct with its longitudinal rim overlying free ends of saidflange portions of said transverse wires.
 13. The cable duct claimed inclaim 11 wherein said section is attached to the outside of said cableduct with its longitudinal rim directed outward.
 14. The cable ductclaimed in claim 9 wherein said section has a U-shaped cross sectionwith wide flanges and straddles said flange portions of said transversewires.
 15. The cable duct claimed in claim 9 wherein said section has aU-shaped cross section with narrow flanges and is attached to theoutside of said cable duct with its narrow flanges directed outward. 16.The cable duct claimed in claim 15 wherein said narrow flanges arestraight.
 17. The cable duct claimed in claim 15 wherein said narrowflanges have a rolled edge.